Substituent effect on photophysical properties and proton transfer process of HBQ derivatives

BackgroundIn view of the potential applications of 10‐hydroxybenzo [h] quinoline (HBQ) in biological probes and organic light‐emission devices, the excited state intramolecular proton transfer (ESIPT) mechanism of HBQ was investigated theoretically in the work.AimsIn order to give a detailed reaction mechanism, the ESIPT of molecular system with hydrogen bond is systematically studied using density functional theory and density functional theoryMethodsUsing density functional theory (DFT) and time‐dependent density functional theory (TDDFT), we investigate the photophysical properties and excited state proton transfer of 10‐hydroxybenzo [h] quinoline (HBQ)derivatives.ResultsThe optimized structure shows that HBQ1 and HBQ2 have no stable structure in S1 state. The analysis of bond length parameters and infrared vibration spectroscopy proved that the substituent groups regulated the hydrogen bond strength in the S0 state.ConclusionTherefore, substitution position will affect the excited state intramolecular proton transfer and the photophysical properties of the molecule.